CPU usage 100% in idle state even after windows re-install

Hi all,

I have a Latitude E5410. 4GB Ram. 32 bit. Win 7 professional.

Recently i found my cpu usage shooting up to 100% and computer becoming super slow. I use original Kaspersky anti virus. I checked for malwares also. I re-installed windows 7 professional.

My battery life have exhausted and now my laptop runs only on AC power and I don't think that has got something to do with this.

I have noticed another strange thing. If I switch off my wireless manager/button then the CPU usage is all right but once I switch it on then the CPU usage reaches  100% and stays there no matter what I do.

Even if i switch it off after that the problem stays. The computer becomes real slow and sluggish and cannot be used. 

I have checked and rechecked but didn't find any virus or malwares.

please help.

Kind regards

Ms.Gizmo